The present invention generally relates to a surgical instrument used during a catheterization procedure, and more particularly to an instrument for accurately measuring the depth below the skin surface to a blood vessel, duct or target organ through which the catheter is to be passed. Even more particularly, one form of the present invention is adapted for use prior to the placement of a vascular hemostasis device to accurately determine the desired size and length of the hemostasis device to seal the puncture or incision.
During catheterization procedures, the nurse or physician will create an opening into an artery or other vessel with a conventional catheter introducer or dilator. In a typical interventional procedure, such as the placement of a vascular catheter, the Seldinger technique is used to gain access to the blood vessel. Initially, a needle trocar is passed through the skin to puncture an opening through the wall of an artery. Next, a dilator may be passed over the trocar to enlarge the diameter of the puncture wound so that it can accommodate an introducer. Once the introducer is positioned in the puncture, a guidewire is inserted through the introducer. Finally, the introducer is removed and the catheter is advanced over the guidewire and into the blood vessel of the patient.
The size of the opening will vary depending on the type of procedure and the size of the catheter which is used. For example, the diameter of the catheter and catheter sheath used in standard angiography procedures is typically between 5 to 8 French (1.67 mm and 2.67 mm, respectively). The diameter of the catheter and catheter sheath used in angioplasty procedures may be 8 (2.67 mm) or 9 (3.33 mm) French. The diameter of the catheter and catheter sheath used in intro-aortic balloon pump procedures is typically between 14 to 16 French (4.67 mm and 5.33 mm, respectively) and the diameter of the catheter and catheter sheath used with cardiopulmonary support systems is typically between 18 and 20 French (6.0 mm and 6.67 mm, respectively). Additionally, the catheter is often twisted or otherwise manipulated as it is advanced to the treatment site, thereby causing a further enlargement of the incision or puncture in the body of the patient.
When the medical procedure is completed and the catheter is removed from the artery or other blood vessel, conventional practice has been to apply external pressure to the entry site until clotting occurs. Because many of the patients undergoing these procedures have been medicated with an anticoagulant such as heparin, the nurse may be required to apply external pressure to the incision site for an extended period of time. The time required to stop bleeding at the incision site is not an efficient use of the nurses time and a painful hematoma or unsightly bruise may still occur at the incision site because the artery will continue to bleed internally until clotting blocks the opening in the artery.
One approach to resolving the problem of sealing the puncture or incision is disclosed in U.S. Pat. No. 4,744,364 granted to Kensey on May 17, 1988, and related U.S. Pat. Nos. 4,852,568 and 4,890,612 granted to Kensey on Aug. 1, 1989, and Jan. 2, 1990, respectively. The first two Kensey patents disclose a device for sealing an opening in the wall of a blood vessel which consists of an elongate tubular body having an anchor member removably disposed therein. The tubular body also includes an ejecting device disposed within the tubular body for forcing the anchor member from the tubular body into the interior of the blood vessel. A retraction suture is secured to the anchor member so that the engagement surface of the anchor member hemostatically engages the inner surface of the blood vessel contiguous with the puncture. The ""612 Kensey patent discloses a device which includes an elongate member having a portion thereof which is adapted to engage portions of the tissue adjacent to the punctured vessel and a sealing portion which extends through the incision to engage the tissue contiguous therewith to seal the puncture. Subsequent patents granted to Kensey et al. are illustrative of improvements to the basic approach described above and generally include an anchor member which is used in combination with a suture and a collagen member to seal an incision and blood vessel.
U.S. Pat. No. 5,411,520 granted to Nash et al. is illustrative of an improvement to the basic approach described above and generally includes a spacer which is movable along a suture to position the spacer between the anchor member and the collagen member to seal the puncture and blood vessel. The spacer is positioned between the collagen member and the anchor to prevent the collagen member from being entering the blood vessel of the patient.
U.S. Pat. No. 5,108,421 granted to Fowler, and assigned to the assignee of the present invention, discloses the use of a xe2x80x9cvessel plugxe2x80x9d type approach wherein the hemostatic closure device is inserted into the incision of the patient and may be positioned in the incision using a locating member such as an elongate balloon type member or a syringe type device. U.S. Pat. No. 5,391,183 granted to Janzen et al. discloses another vessel plug type approach wherein one or more oversized vessel plugs are inserted into the incision using a device with a plunger member.
An important consideration in each of the sealing devices described above, is to accurately identify the location of the blood vessel below the access sheath or skin surface of the patient. This is particularly true for the xe2x80x9cvessel plugxe2x80x9d types of sealing devices because the collagen plug is intended to be positioned in contact with the outer surface of the wall of the blood vessel without extending into the blood vessel. To accomplish this, it is important to accurately determine the depth of the puncture and accurately position the delivery device for the collagen plug. It is also desirable to apply a sufficient amount of hemostasis promoting material into the puncture so that the bleeding from the blood vessel is rapidly and securely stopped.
It is accordingly an object of the present invention to provide a measuring device for use with hemostatic closure devices for accurately assessing the depth of the blood vessel beneath the skin of the patient.
It is yet another object of the present invention to provide a measuring device which is simple to use and manufacture and which provides an accurate and reproducible measurement.
In one form of the present invention, the measuring device includes an elongate tubular member having a proximal end, a distal end and a lumen extending therebetween. The distal end portion of the elongate member is preferably rounded and includes a radially expandable member spaced slightly behind the distal end. The expandable member is preferably in communication with a proximally located actuation member via the lumen. The proximal end of the elongate member preferably includes a deformable member, such as a squeeze bulb or disk member on the proximal end of the elongate member. The deformable member may be mechanically or fluidly interconnected with the expandable member by using a wire which extends the length of the measuring device or using fluid pressure to expand the expandable member. The outer circumference of the elongate member preferably includes markings thereon to provide the user with an indication of the depth of the expandable member relative to the proximal end of the access heath or skin of the patient. The markings may include graduations, bands, stripes or other visually observable indicia. In use, the measuring device is inserted in a conventional manner, such as through a procedure sheath or tear apart sheath, and into the puncture once the procedure has been completed. The user may then squeeze the actuation member on the proximal end of the measuring device to cause the expansion of the bulb-type member on the distal end thereof. The user may then withdraw the measuring device in the puncture until resistance is felt. The existence of resistance to the withdrawal of the measuring device is indicative that the expandable member has contacted the wall of the blood vessel adjacent to the puncture. The user may then view the markings on the exterior of the measuring device and note the depth of the puncture. The appropriate hemostasis or other device may then be selected according to the determined depth and the puncture may be sealed using one of the commercially available hemostasis devices.
In accordance with another form of the present invention, the elongate member may include a further lumen therein to allow the measuring device to be passed over a guidewire during insertion of the measuring device into the puncture.
The present invention may also be modified to include a slidable member, such as a marking ring, on the outer surface of the measuring device so that once the location of the blood vessel is determined, the slidable member may be moved into contact with the skin of the patient. The measuring device may then be removed from the puncture and the user may choose the appropriate sealing device by observing the depth indicated by the position of the slidable member on the measuring device.
An advantage of the present invention is that it is simple to manufacture and use.
A further advantage of the present invention is that it may be used in nearly any medical procedure where it is desirable to accurately and consistently identify the depth of a puncture for sheath placement or for subsequent insertion of a medical device such as a hemostatic puncture closure device or sealing device.